Administrative Supplements to Support Undergraduate Summer Research Experiences - Inhibition of Human Islet Amyloid Polypeptide Aggregation

摘要 胰岛淀粉样多肽（IAPP）的淀粉样聚集与2型糖尿病β细胞死亡相关 （T2D）。IAPP是β细胞分泌的一种与胰岛素共分泌的肽类激素，是淀粉样蛋白的主要来源之一 并且在体外容易形成淀粉样纤维。越来越多的证据表明，抑制IAPP聚集和 聚集介导的细胞毒性，我们的长期目标，是一个有吸引力的治疗策略，以防止β细胞 死亡并阻止T2 D中糖尿病状况的进展。随着冷冻电镜技术的最新进展， 结构生物学，IAPP原纤维的原子结构已经解决，由平行对齐的β-折叠组成 作为交叉β核。然而，由于低聚物中间体的异质性和瞬时性， 在聚集过程中，从分离的单体到最终原纤维的过程的许多细节仍然是未知的。与 淀粉样蛋白毒性可能通过与细胞膜的直接或间接相互作用介导， 研究IAPP在膜环境中的聚集很重要。越来越多的证据表明 不同淀粉样蛋白疾病之间的病理相关性-例如，T2 D是神经退行性疾病的危险因素 疾病，包括阿尔茨海默病和帕金森病;和细菌淀粉样蛋白可能有助于发病 神经退行性疾病和糖尿病。不同的淀粉样蛋白之间的交叉相互作用， 分子水平可能有助于相应疾病之间的病理相关性。我们有 证明了新的纳米颗粒可以被工程化以减轻hIAPP聚集和细胞毒性。 尽管有许多优点，包括能够跨越生物屏障，但纳米医学的主要问题是， 发展包括与免疫反应相关的潜在毒性和缺乏特异性。在这 MIRA更新申请，PI建议继续揭示IAPP的分子机制 聚集和探索新的纳米颗粒方法来抑制IAPP聚集和毒性， 以下方向：1）IAPP聚集和与膜的相互作用; 2） hIAPP和其他淀粉样蛋白;和3）用纳米颗粒减轻IAPP淀粉样变性 通过内源性抑制剂官能化。PI实验室将联合收割机计算建模与实验 表征和验证。计算建模可以帮助弥合时间和长度尺度的差距 实验观察和潜在的分子系统之间，不仅提供分子 对实验观察的见解，但也提供实验可检验的假设。这样的组合 计算和实验的方法可以提高研究效率，缩短发现周期。的 拟议研究的结果将有助于了解疾病机制和发现新的治疗方法。 目标（项目1）;为T2 D和其他淀粉样蛋白之间的病理相关性提供分子基础 疾病，以及细菌感染和生态失调对T2 D发病的贡献（项目2）;并提供 设计具有高特异性和降低纳米毒性的抗淀粉样蛋白纳米颗粒的新方法（项目3）。 1

Abstract Amyloid aggregation of islet amyloid polypeptide (IAPP) is associated with β-cell death in type-2 diabetes (T2D). IAPP, a peptide hormone co-secreted with insulin by β-cells, is one of the most amyloidogenic proteins and readily forms amyloid fibrils in vitro. Mounting evidence suggests that inhibition of IAPP aggregation and aggregation-mediated cytotoxicity, our long-term goal, is an attractive therapeutic strategy to prevent β-cell death and stop the progression of diabetic conditions in T2D. With the recent advances of Cryo-EM in Structural Biology, atomic structures of IAPP fibrils have been solved, comprised of parallel in-register β-sheets as the cross-β core. However, due to heterogeneous and transient nature of oligomer intermediates populated during aggregation, many details of the process from isolated monomers to final fibrils are still unknown. With amyloid toxicity likely mediated by direct or indirect interactions with the cell membrane, it is increasingly important to study the aggregation of IAPP in the membrane environment. Increasing evidence also suggests pathological correlations between different amyloid diseases – e.g., T2D is the risk factor of neurodegenerative diseases, including Alzheimer’s and Parkinson’s diseases; and bacterial amyloids may contribute to the onset of neurodegenerative diseases and diabetes. Cross-interactions between different amyloid proteins at the molecular level might contribute to the pathological correlation between corresponding diseases. We have demonstrated that novel nanoparticles can be engineered to mitigate hIAPP aggregation and cytotoxicity. Despite many advantages including the ability to cross biological barriers, major concerns for nanomedicine development include potential toxicity associated with immune responses and the lack of specificity. In this MIRA renewal application, the PI proposes to continuously uncover molecular mechanisms of IAPP aggregation and to explore novel nanoparticle approaches to inhibit IAPP aggregation and toxicity in the following directions: 1) IAPP aggregation and interactions with the membrane; 2) cross-interactions between hIAPP and other amyloidogenic proteins; and 3) mitigation of IAPP amyloidosis with nanoparticles functionalized by endogenous inhibitors. The PI lab will combine computational modeling with experimental characterization and validation. Computational modeling can help bridge the time and length scale gaps between experimental observations and the underlying molecular systems, providing not only molecular insights to experimental observations but also offering experimentally-testable hypotheses. Such a combined computational and experimental approach can improve research efficiency and shorten discovery cycle. The outcome of the proposed studies will help understand disease mechanisms and discover novel therapeutic targets (Project 1); provide molecular bases for pathological correlations between T2D and other amyloid diseases, and the contribution of bacterial infections and dysbiosis to the onset of T2D (Project 2); and offer new approaches to design anti-amyloid nanoparticles with high specificity and reduced nanotoxicity (Project 3). 1